Odor control additives have been conventionally incorporated into substrates for a variety of reasons. For instance, U.S. Pat. No. 6,225,524 to Guarracino, et al. describes a substrate having an odor control composition that includes an absorbent gelling material and silica. Likewise, U.S. Pat. No. 6,376,741 to Guarracino, et al. describes a substrate having an odor control composition that includes silica and a zeolite (i.e., crystalline aluminosilicate). For instance, one type of silica said to be preferred in Guarracino, et al. ('524 patent) is amorphous silica having a particle size of 4-12 microns and a pore volume of 1-2 g/ml. Another type of preferred silica is said to be a silica gel having a medium pore diameter of from 90 to 110 angstroms, a surface area of from 250 m2/g to 350 m2/g, and an average particle size of from 63 to 200 microns.
Unfortunately, conventional odor control compositions, such as described above, have proven ineffective in obtaining the full level of odor control desired in many applications. For example, most conventional silica has a relatively large average size (i.e., micron scale). This large size results in a coating with a small available surface area for contacting the odorous compound, and may in fact reduce the porosity of a substrate to which it is applied. The large size of the particles also allows them to be easily rubbed off of the substrate, which results in a reduction in the coating over time. The porosity of some types of conventional silica may also reduce uniformity and stability.
As such, a need exists for an odor control composition that may exhibit improved odor control properties, particularly when applied to a substrate.